17.6.2.2. Pipe Pressure

Used in any structural analysis, Pipe Pressure is useful for pipe stress analysis and pipe design. Pipe Pressure is applied only to pipes in the form of line bodies.

This page includes the following sections:

Analysis Types

Pipe Pressure is available for the following analysis types:

Dimensional Types

The supported dimensional types for the Pipe Pressure boundary condition include:

  • 3D Simulation. For 3D structural analyses, a Pipe Pressure load applies a constant, tabular, or functional variation of pressure to one or more line bodies which are set to be pipes.

Geometry Types

The supported geometry types for Pipe Pressure include:

  • Wire Body/Line Body/Beam: Supported for Line Bodies only.

Topology Selection Options

The supported topology selection options for the Pipe Pressure boundary condition include:

  • Edge

Define By Options

The Define By options for Pipe Pressure, by default, is program controlled. Internal and external pressures are input on an average basis. By default, when the pipe is subjected to internal and external pressures, the end-cap pressure effect of the pipe is included. This implies that the end caps are always in equilibrium, that is, no net forces are produced.

Magnitude Options

The supported Magnitude options for Pipe Pressure include the following:

  • Constant

  • Tabular (Time Varying)

  • Tabular (Step Varying): Supported for Static Structural analysis only.

  • Tabular (Spatially Varying)

  • Function (Time Varying)

  • Function (Spatially Varying)

Applying a Pipe Pressure Boundary Condition

To apply a Pipe Pressure:

  1. On the Environment Context tab, open the Loads drop-down menu and select Pipe Pressure. Alternatively, right-click the Environment tree object or in the Geometry window and select Insert>Pipe Pressure.

  2. Define the Scoping Method as either Geometry Selection or Named Selection and then specify the geometry. Pipe Pressure can only be scoped to line bodies which are set to be pipes.

  3. Define Magnitude as a constant, tabular, or functional input.

  4. Select Loading to be Internal or External according to your problem.

Details Pane Properties

The selections available in the Details pane are described below.

CategoryProperty/Options/Description
Scope

Scoping Method: Options include:

  • Geometry Selection: Default setting, indicating that the boundary condition is applied to a geometry or geometries, which are chosen using a graphical selection tool.

    • Geometry: Visible when the Scoping Method is set to Geometry Selection. Displays the type of geometry (Body, Face, etc.) and the number of geometric entities (for example: 1 Body, 2 Edges) to which the boundary has been applied using the selection tools.

  • Named Selection: Indicates that the geometry selection is defined by a Named Selection.

    • Named Selection: Visible when the Scoping Method is set to Named Selection. This field provides a drop-down list of available user–defined Named Selections.

Definition

Type: Read-only field that displays boundary condition type - Pipe Pressure.

Magnitude: Input field to define the magnitude of the Pipe Pressure. This value can be defined as a Constant or in Tabular form, as well as Imported.

Suppressed: Include (No - default) or exclude (Yes) the boundary condition.

Loading: Specify whether the loading is Internal or External.

Mechanical APDL References and Notes

The following Mechanical APDL element types are applicable for this boundary condition. Both elements are based on Timoshenko beam theory which includes shear-deformation effects.

  • PIPE288: 3D two-node pipe

  • PIPE289: 3D three-node pipe.

  • ELBOW290: special 3D three-node pipe used for modeling curved pipes. This element is also used when Pipe Idealization is scoped to a line body modeled as pipe and meshed with higher order elements. PIPE289 is converted ELBOW290.

Displaying Contours and Displaced Shapes on Line Bodies: The contour results line bodies are expanded to be viewed on the cross section shape, but only one actual result exists at any given node and as a result no contour variations across a beam section occur. Therefore, for Mechanical APDL plot comparison, full graphics inside /POST1 should be used when comparing numerical values.

API Reference

For specific scripting information, see the Pipe Pressure section of the ACT API Reference Guide.